1. Field of the Invention
The present invention relates to an oil quantity monitoring system for a motorcycle provided with a hydraulic clutch brought by hydraulic pressure into a neutral state where power of an engine is interrupted from a drive wheel side and into a drive state where the power of the engine is applied to the drive wheel side.
2. Description of Background Art
A hydraulic switch for detecting whether or not hydraulic pressure is equal to or greater than a prescribed value for a motorcycle is used to determine whether or not a proper quantity of lubricating oil (hereinafter also called oil) is present. See, for example, Japanese Patent Laid-open No. Hei 10-238327 (FIG. 5, paragraph [0018]).
Motorcycles are marketed that are mounted with a hydraulic clutch thereon which is switched by hydraulic pressure between a neutral state and a drive state by use of oil.
In a motorcycle mounted with a hydraulic clutch thereon, oil is shared by a lubricating system disposed around an engine including a crankshaft, a cam shaft, a transmission main shaft. In addition, the oil is used for the engagement/disengagement control of the hydraulic clutch.
However, motorcycles whose various portions share oil as described above have a problem as set forth below. If an oil quantity is lowers to or is below a lower limit of a prescribed value, hydraulic pressure may be momentarily lowered due to the inclination of an oil level resulting from sudden deceleration, sudden starting, driving on a sloping road or the like. In such a case, the hydraulic clutch comes into a disengagement state to degrade a feeling of the ride.